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import {  CHACHA20_NONCE_BYTES,  chacha20poly1305Seal,  chacha20poly1305Open,  HCHACHA20_NONCE_BYTES,  HCHACHA20_OUTPUT_BYTES,  hchacha20} from "./deps.ts";
export const KEY_BYTES: number = 32;export const NONCE_BYTES: number = 24;export const PLAINTEXT_BYTES_MAX: bigint = 274877906880n;export const CIPHERTEXT_BYTES_MAX: bigint = 274877906896n;export const AAD_BYTES_MAX: bigint = 18446744073709551615n;export const TAG_BYTES: number = 16;
export function seal(  key: Uint8Array,  nonce: Uint8Array,  plaintext: Uint8Array,  aad: Uint8Array): null | { ciphertext: Uint8Array; tag: Uint8Array; aad: Uint8Array; } {  if (key.byteLength !== KEY_BYTES) {    return null;  }
  if (nonce.byteLength !== NONCE_BYTES) {    return null;  }
  if (plaintext.byteLength > PLAINTEXT_BYTES_MAX) {    return null;  }
  if (aad.byteLength > AAD_BYTES_MAX) {    return null;  }
  const chacha20poly1305Key: Uint8Array = new Uint8Array(    HCHACHA20_OUTPUT_BYTES  );
  hchacha20(    chacha20poly1305Key,    key,    nonce.subarray(0, HCHACHA20_NONCE_BYTES)  );
  const chacha20poly1305Nonce: Uint8Array = new Uint8Array(    CHACHA20_NONCE_BYTES  );
  chacha20poly1305Nonce.set(    nonce.subarray(HCHACHA20_NONCE_BYTES, nonce.byteLength),    4  );
  const sealed: null | {    ciphertext: Uint8Array;    tag: Uint8Array;    aad: Uint8Array;  } = chacha20poly1305Seal(    chacha20poly1305Key,    chacha20poly1305Nonce,    plaintext,    aad  );
  chacha20poly1305Key.fill(0x00, 0, chacha20poly1305Key.byteLength);
  return sealed;}
export function open(  key: Uint8Array,  nonce: Uint8Array,  ciphertext: Uint8Array,  aad: Uint8Array,  receivedTag: Uint8Array): null | Uint8Array {  if (key.byteLength !== KEY_BYTES) {    return null;  }
  if (nonce.byteLength !== NONCE_BYTES) {    return null;  }
  if (ciphertext.byteLength > CIPHERTEXT_BYTES_MAX) {    return null;  }
  if (aad.byteLength > AAD_BYTES_MAX) {    return null;  }
  if (receivedTag.byteLength !== TAG_BYTES) {    return null;  }
  const chacha20poly1305Key: Uint8Array = new Uint8Array(    HCHACHA20_OUTPUT_BYTES  );
  hchacha20(    chacha20poly1305Key,    key,    nonce.subarray(0, HCHACHA20_NONCE_BYTES)  );
  const chacha20poly1305Nonce: Uint8Array = new Uint8Array(    CHACHA20_NONCE_BYTES  );
  chacha20poly1305Nonce.set(    nonce.subarray(HCHACHA20_NONCE_BYTES, nonce.byteLength),    4  );
  const plaintext: null | Uint8Array = chacha20poly1305Open(    chacha20poly1305Key,    chacha20poly1305Nonce,    ciphertext,    aad,    receivedTag  );
  chacha20poly1305Key.fill(0x00, 0, chacha20poly1305Key.byteLength);
  return plaintext;}